Recent advancements in wireless communications require an RF receiver that can support a wide dynamic range of analog input signals. A digital step attenuator (DSA) is widely used in the RF receivers with wideband and multiband applications. The DSA is an analog attenuator whose attenuation is controlled digitally. The DSA can be integrated with the RF receiver or it can be external to the RF receiver. However, it is preferred to integrate the DSA in the RF receiver since it reduces the overall board area and also the cost.
Due to high dynamic range of analog input signals received by the RF receiver, the DSA is required to support a large range of attenuations. This ensures that a voltage level reaching the other components of the RF receiver post DSA is within a defined limit, so as to ensure normal operation of the RF receiver. Thus, DSA is important for ensuring reliability of the components used in the RF receiver. A DSA, that supports the high dynamic range of analog inputs signals, is difficult to integrate in the RF receiver. This is because of large noise figure that it adds to the RF receiver.